This invention relates to a plastic one-piece latch particularly suitable for retaining in a closed state a lid serving to close a fuel inlet as in an automobile.
As is widely known, a lid is swingably attached through the medium of a hinge to the fuel inlet of an automobile. This lid is provided at the free end thereof with a bolt which has a hook raised from the leading end thereof and which is disposed in a direction such that when the lid is set in position to close the fuel inlet, the bolt thrusts into the fuel inlet. When the lid is closed after a refill of fuel, the hook on the bolt snaps into engagement with the latch which is provided on the interior of the free edge of the fuel inlet. Once this engagement is established, the lid remains fast on the fuel inlet and protects the fuel in the fuel tank from being stolen. It will not open unless and until the bolt is rotated around its axis with a special key. The conventional latch of this principle is a shaped article obtained by bending a metallic leaf spring in the general shape of the letter U. One of the two straight legs of the U-shaped body of the latch is fastened to an edge of the fuel inlet and the other straight leg is used as an engaging piece such that when the lid is being brought to its closed position, it is gradually pressed down by the pressure exerted by the hook of the bolt which slides thereon and, at the time that the lid is completely closed on the fuel inlet, the tip of the hook snaps into engagement with the free end of the engaging piece.
Since this latch is made of a metal, it rusts after prolonged use. Not infrequently, it may be corroded even to the point where it becomes no longer serviceable and requires replacement. Further since the latch is made of a thin metallic leaf spring and is fastened in a protruding manner to the edge of the fuel inlet, there is a fair possibility that the attendant at a filling station, while inserting a fuel nozzle into the fuel inlet through the open lid for the purpose of refilling the fuel tank, will accidentally scratch his fingers on the latch.
Further owing to the error involved in the fabrication and assemblage of the bolt and the latch, the position at which the hook on the bolt and the edge of the latch come into engagement at the time of the closure of the lid may be displaced, though slightly, in the direction of the depth of the fuel inlet In extreme cases, such displacement may cause the hook to fail to snap into engagement with the latch at the time that the lid is completely closed on the fuel inlet or the hook may snap into engagement with the latch before the lid is completely closed; In such a case, the lid may clatter against the fuel inlet, necessitating some measure for eliminating the displacement. Moreover, since the peripheral edge of the fuel inlet is exposed from the outer shell of the automobile, it is coated with the same paint as the outer shell. The edge of the fuel inlet, therefore, must be protected so that its coated surface will not be damaged when the lid is opened and closed. If the coated surface should be scratched or otherwise damaged, the inlet will eventually rust through. As a combined measure for precluding the positional displacement and the infliction of damage, there has heretofore been adopted a practice of fastening rubber pieces at several points on the outer edge of the lid, i.e. at points such that the rubber pieces will come into contact with the coated surface of the peripheral edge of the fuel inlet when the lid is completely closed on the fuel inlet. These rubber pieces protect the coated surface against otherwise possible infliction of damage by the outer edge of the lid. They further serve the purpose of absorbing any dimensional error by causing the hook to snap into engagement with the latch after the rubber pieces have been compressed to a certain extent under the pressure exerted by the lid. The conventional lid, therefore, has been required to be provided in advance with claws for holding such rubber pieces fast in position for effectively fulfilling the purposes mentioned above. It further requires provision of screws for fastening the latch to the fuel inlet.